[Interest] Dynamically created item destroyed with original parent despite reparenting

[Peter Klosowski]

On Mon, Dec 21, 2015 at 2:03 AM, Elvis Stansvik <elvstone at gmail.com> wrote:

> 2015-12-20 16:39 GMT+01:00 Peter Klosowski <kloffy at gmail.com>:
> > Unfortunately, the solution Elvis provided does not work for me.
> Instead, I
> > get the following error:
> >
> > TypeError: Property 'push' of object [object Object] is not a function
> >
>
> Aha, I only tested it briefly in qmlviewer, so I didn't see those
> errors. So then it only seemingly worked for me.
>

No worries, it would have been awesome if the solution was that simple.


> > Of course, that means the blue rectangle stays on the screen, but only
> > because the code after the error never gets executed (i.e. oldParent
> never
> > gets destroyed).
> >
> > Nevertheless, I believe this would be the right track, if it is possible
> at
> > all.
>
> Yes I think from the docs I found ("Any object assigned to an item's
> data property becomes a child of the item within its QObject hierarchy
> [...]"), it should be possible somehow. Question is how to do that
> assignment. Or perhaps the docs are a little misleading, and by
> "assignment" they simply mean declaring an item inside another, and
> there's no way to do this dynamically..? Would be kind of weird if it
> wasn't possible though.
>

I agree, that seems like a pretty glaring omission. Digging into the
sources (qt/qdeclarativelist.cpp), it appears that lists have a method for
appending items, but as far as I can tell it looks like it is not
accessible via QML. In the worst case, I could probably implement the
newParent in C++ and wrap the call to append in a custom Q_INVOKABLE
function. So at least I have a contingency plan now...


> Elvis
>
> >
> > Best regards,
> > kloffy
> >
> >
> > On Mon, Dec 21, 2015 at 1:28 AM, Peter Klosowski <kloffy at gmail.com>
> wrote:
> >>
> >> Thank you all for your suggestions. This is an artificial example to
> >> illustrate the behavior that I am having problems with. I could also
> >> dynamically create the parent, that is not of relevance to my problem.
> >>
> >> On the other hand, the information that Elvis provided about the
> >> distinction between visual parent and QObject parents seems to hit the
> nail
> >> on the head. I will test and report back!
> >>
> >> Best regards,
> >> koffy
> >>
> >> On Mon, Dec 21, 2015 at 1:10 AM, Elvis Stansvik <elvstone at gmail.com>
> >> wrote:
> >>>
> >>> 2015-12-20 16:05 GMT+01:00 Personal Gmail
> >>> <siamak.rahimi.motem at gmail.com>:
> >>> > Hi Elvis ,
> >>> > Can we destroy() old parent which is not a component ? In other
> words,
> >>> > Is
> >>> > not the destroy only for component created dynamically ?
> >>> > I think oldParent.destory is problematic.
> >>>
> >>> Aha, now I see what you mean. I've never actually used QML myself, and
> >>> didn't know this (and that setting transparency to 0 is actually the
> >>> recommended way to remove it from the visual scene hierarchy).
> >>>
> >>> But I think you're right, and that Peter should probably do that
> >>> instead, or otherwise make sure his old parent is created dynamically.
> >>>
> >>> In any case, I tried
> >>>
> >>> newParent.data.push(target);
> >>>
> >>> and it seems to work, the blue rect remains. But I realize now that
> >>> .push is not documented in Qt 5 documentation
> >>> (http://doc.qt.io/qt-5/qml-list.html) so perhaps this is not
> >>> guaranteed to be supported. In the old 4.x docs, it says there are
> >>> limitations on .push (it'll only create a new list, not modify an
> >>> existing, but don't know if this holds for 5.x).
> >>>
> >>> Elvis
> >>>
> >>> >
> >>> > On 20 Dec 2015, at 17:02, Elvis Stansvik <elvstone at gmail.com> wrote:
> >>> >
> >>> > Elvis
> >>> >
> >>> >
> >>> _______________________________________________
> >>> Interest mailing list
> >>> Interest at qt-project.org
> >>> http://lists.qt-project.org/mailman/listinfo/interest
> >>
> >>
> >
> >
> > _______________________________________________
> > Interest mailing list
> > Interest at qt-project.org
> > http://lists.qt-project.org/mailman/listinfo/interest
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/interest/attachments/20151221/71495ee4/attachment.html>